Lighting industry term -CCT
Each light source has a natural color tone to its light. In general, to produce warmer tones and a more comfortable/soothing light (often used for general lighting), purchase lights that have a 2700-3200 k (kelvin) rating.
To produce truer colors and a more natural light (Dressing Rooms, over fruit and veggies, areas where you want the truest color without glare), 4000 – 4500 K. For day white or bright light (task-spaces, offices), 5500-6000 K. The Color Rating Index (CRI) is basically a measurement of how a light shows a product’s true color.
So CCT=color temperature，There are more color temperature options.